The present disclosure relates to corona charging device cleaning apparatus and methods of cleaning corona charging devices.
Cross-referenced is a co-pending commonly assigned U.S. patent application Ser. No. 11/327,585 filed Jan. 6, 2006 by Michael F. Zona et al. entitled PIN ARRAY SCOROTRON CHARGING SYSTEM FOR SMALL DIAMETER PRINTER PHOTORECEPTORS, the disclosure of which is incorporated herein by reference in its entirety. That application discloses a compact corona charging system for uniformly charging a small radius moving surface. The charging system includes integral independently controllable leading and trailing corona charging sections for sequentially charging a small radius moving surface. The leading corona charging section includes a first elongated corona discharge member transverse to the moving surface and connectable to a first high voltage current supply and a first corona screen grid member connectable to a first screen grid control voltage supply. The trailing corona charging section includes a second elongated corona discharge member transverse to the moving surface and connectable to a second high voltage current supply and a second corona screen grid member connectable to a second screen grid control voltage supply and electrically independent of the first corona screen grid member and the first screen grid control voltage supply. The first corona screen grid member is interposed between the first elongated corona discharge member and the small radius moving surface. The second corona screen grid member is interposed between the second elongated corona discharge member and the small radius moving surface.
Charging photoreceptor drums has been accomplished using contact charging methods. Some methods use bias charging rolls due to their small size and ease of manufacture. Charge roll technology uses high AC voltages for uniform charging that generate reactants on the photoreceptor transport layer which can degrade the transport layer causing physical wearing of the surface. This wearing limits the useable life of the photoreceptor device, which in turn drives up system costs. These costs can be especially high in color systems that may have multiple photoreceptor devices.
Other charging methods implement corona charging systems that include electric corona discharge wires or pin arrays. These systems are known as corotrons or scorotrons (the latter having discharge screen control grids). The systems use corona discharge to generate ions that are directed to the surface of the drums or onto belts that are wrapped around drums.
A corotron usually consists of a thin wire(s) that is stirring within a metal enclosure which is open on one face. The wire is subjected to several thousand volts. The intense electric fields around the wires cause the air molecules to ionize, and thus charged ions, whose polarity depends on that of the high voltage, are driven onto the photoconductor surface. A typical corotron may have multiple individual corona wires placed at a relatively small distance from the photoconductor surface.
A scorotron usually consists of a series of corona wires with a screen or grid composed of larger diameter wires placed between the corona wires and the photoconductor surface. The screen wires are biased to a potential close to that desired at the photoconductor. The photoreceptor charging process ceases when the surface potential reaches the potential of the screen grid bias.